Engine-motor hybrid vehicle control apparatus and method having engine performance Lessening compensation

Abstract

In an engine-motor hybrid vehicle, vehicle drive regions are divided into a plurality of groups specified by a plurality of operation state variables. A learning variable set for each drive region is updated according to an amount of a power state of an engine, when the vehicle is in a steady state running. The learning variable indicates a change in the power state amount with age. When an engine power demand value is determined, it is corrected by using the learning variable of a selected drive region to calculate a corrected engine power demand value compensating a change in the engine with age. In this manner, the engine power is controlled.

What is claimed is:  
     
       1. A control apparatus for an engine-motor hybrid vehicle having an engine for generating an engine power, a power transmission device including a rotary electric machine converting the engine power into an electric power to generate a driving power of the vehicle, and an electricity storage device for supplying the electric power to the rotary electric machine and receiving the electric power therefrom, the control apparatus determining an engine power demand value to be generated by the engine based on a vehicle driving power demand value for driving the vehicle and a charge/discharge power demand value for charging and discharging the electricity storage device, and controlling the engine power based on the engine power demand value, the control apparatus comprising: 
       means for setting a learning variable for each of operation regions of the vehicle, the operation regions being specified by a plurality of operation state variables representing respective operation state parameters of the vehicle;  
       means for determining a power state amount indicating a predetermined power state of the engine including a charge/discharge power when a predetermined operation condition establishes, and updating the learning variable of the operation region selected according to a value of the operation state variable, based on the power state amount;  
       means for correcting the engine power demand value based on the learning variable; and  
       means for controlling the engine power based on the corrected engine power demand value.  
     
     
       2. A control apparatus according to claim  1 , wherein the operation state variable includes a vehicle driving torque and at least one of a vehicle speed and a number of rotations of an output shaft of the engine. 
     
     
       3. A control apparatus according to claim  1 , wherein the learning variable is updated to a value intermediate between a previously updated value thereof and a current value thereof determined according to the power state amount, each time the predetermined operation condition establishes. 
     
     
       4. A control apparatus according to claim  1 , wherein the predetermined operation condition is an operation state in which a variation of a predetermined state amount associated with any one of a vehicle driving torque demand value, the vehicle driving power demand value, and the engine power demand value continues within a predetermined range for a predetermined period of time. 
     
     
       5. A control apparatus according to claim  1 , wherein the power state amount includes a deviation between the charge/discharge power demand value and an actual charge/discharge power of the electricity storage device. 
     
     
       6. A control apparatus for an engine-motor hybrid vehicle having an engine, a power transmission device including a first rotary electric machine connected with an output shaft of the engine and determining a number of rotations of the engine and a second rotary electric machine connected with an output shaft of the vehicle and determining a driving force of the vehicle, and an electricity storage device for supplying an electric power to the first and second rotary electric machines and receiving the electric power therefrom, the control apparatus comprising: 
       means for calculating a vehicle driving torque demand value based on information of operation of an accelerator pedal, a braking pedal, and a shift lever;  
       means for calculating a vehicle driving power demand value based on the vehicle driving torque demand value and a vehicle speed;  
       means for calculating a charge/discharge power demand value based on a storage state of the electricity storage device;  
       means for calculating an engine power demand value based on the vehicle driving power demand value and the charge/discharge power demand value;  
       means for calculating an engine speed demand value based on the engine power demand value and a stored characteristic of the engine;  
       means for calculating a first torque demand value to be generated by the first rotary electric machine based on the engine speed demand value;  
       means for calculating a second torque demand value to be generated by the second rotary electric machine based on the first torque demand value and the vehicle driving torque demand value;  
       means for controlling the first and second rotary electric machines, based on the first and second torque demand values, respectively;  
       means for setting a learning variable learnable for each of the operation regions, the operation regions being specified by an operation state variable including the vehicle driving torque and at least one of the vehicle speed and the number of rotations of the output shaft of the engine;  
       means for determining a power state amount indicating a predetermined power state of the engine including a charge/discharge power when a predetermined vehicle operation condition regarded as a steady operation state establishes, and updating the learning variable of the operation region selected according to a value of the operation state variable, based on the power state amount;  
       means for correcting the engine power demand value or the vehicle driving power demand value based on the learning variable; and  
       means for controlling the engine power based on the corrected engine power demand value.  
     
     
       7. A control method for an engine-motor hybrid vehicle having an engine, a power transmission device including an electric motor connected between the engine and wheels, and a storage electricity storage device for supplying an electric power to the motor and receiving the electric power therefrom, the control method comprising the steps of: 
       detecting whether a vehicle is traveling under a predetermined steady state;  
       detecting an imbalance of charge and discharge of the storage electricity storage device;  
       detecting a lessening of an engine performance from a maximum performance efficiency point when the detected imbalance is outside of a predetermined range; and  
       changing an engine control based on a detection result of the lessening detecting step.  
     
     
       8. A control method according to claim  7 , wherein the changing step includes: 
       calculating an engine control correction value when the predetermined steady state and the lessening are detected; and  
       controlling the engine based on predetermined control parameters including the calculated engine control correction value thereby to operate the engine at the maximum performance efficiency point.  
     
     
       9. A control method according to claim  8 , wherein the engine control correction value is updated to reduce the imbalance of charge and discharge of the storage electricity storage device. 
     
     
       10. A control method according to claim  9 , wherein the engine control correction value is provided for each of a plurality of operation areas of the vehicle. 
     
     
       11. A control apparatus for an engine-motor hybrid vehicle having an engine, a power transmission device including a rotary electric machine converting at least a part of the engine power thereof into an electric power and generating at one part of a driving power of the vehicle, and an electricity storage device for supplying an electric power to the rotary electric machine and receiving the electric power therefrom, the control apparatus comprising: 
       means for detecting operation state data of the vehicle;  
       means for determining a vehicle driving power demand value for driving the vehicle based on the operation state data;  
       means for detecting remaining capacity data of a remaining capacity of the electricity storage device;  
       means for determining charge and discharge control amounts of the electricity storage device such that the remaining capacity of the electricity storage device falls within a predetermined range based on the remaining capacity data;  
       means for controlling the engine to generate an engine power satisfying the vehicle driving power demand value and the charge and discharge control amounts; and  
       means for altering charge and discharge control amounts in a direction in which a voltage change is restrained, when the operation state changes in such a manner that an excess voltage change occurs in the electricity storage device.  
     
     
       12. A control apparatus according to claim  11 , wherein the excess voltage change is caused to occur in the electricity storage device when a depression stroke of an accelerator changes. 
     
     
       13. A control apparatus according to claim  11 , wherein the excess voltage change is caused to occur in the electricity storage device when the vehicle driving power demand value changes. 
     
     
       14. A control apparatus according to claim  11 , wherein the altering means decreases the absolute value of the charge/discharge control amount, when a change in the operation state is in a vehicle-accelerating direction and that the charge/discharge control amount is in a discharge side, or when a change in the operation state is in a vehicle-decelerating direction and that the charge/discharge control amount is in a charge side. 
     
     
       15. A control apparatus according to claim  11 , wherein the altering means increases the absolute value of the charge/discharge control amount, when a change in the operation state is in a vehicle-accelerating direction and that the charge/discharge control amount is in a charge side, or when a change in the operation state is in a vehicle-decelerating direction and that the charge/discharge control amount is in a discharge side. 
     
     
       16. A control apparatus according to claim  11 , wherein the altering means continues alteration of the charge and discharge control amounts for a predetermined period of time after detecting the operation state change which causes an excessive voltage change in the electricity storage device. 
     
     
       17. A control apparatus according to claim  11 , wherein the altering means continues alteration of the charge and discharge control amounts for a predetermined period of time after termination of the operation state change which causes an excessive voltage change in the electricity storage device. 
     
     
       18. A control apparatus for an engine-motor hybrid vehicle comprising: 
       an engine having an output shaft;  
       an electricity storage device;  
       a power transmission device for transmitting an energy between the engine and the electricity storage device as well as a drive shaft of the vehicle, the power transmission device having an input shaft and an output shaft; and  
       an electronic control unit for controlling the power transmission device,  
       wherein the power transmission device includes:  
       a first rotary electric machine having a first rotor mechanically connected with the output shaft of the engine through the input shaft of the power transmission device, and a second rotor connected with the first rotor such that an electromagnetic energy is transmitted between the second rotor and the first rotor and mechanically connected with the output shaft of the power transmission device, the first rotary electric machine transmitting an energy between the engine and the electricity storage device;  
       a second rotary electric machine having a rotor mechanically connected with the output shaft of the power transmission device and transmitting an electromagnetic energy between the electricity storage device and the output shaft of the power transmission device;  
       a connection mechanism connecting the output shaft of the engine with the input shaft of the power transmission device while allowing a slight relative rotary motion; and  
       a rotation restraining mechanism restraining the input shaft of the power transmission device.  
     
     
       19. A control apparatus according to claim  18 , wherein the rotation restraining mechanism has a first restraining position at which the first rotor of the first rotary electric machine is restrained, a second restraining position at which the second rotor of the first rotary electric machine is restrained, and an unrestrained position at which the first and second rotors of the first rotary electric machine are not restrained. 
     
     
       20. A control apparatus for an engine-motor hybrid vehicle comprising: 
       an engine having an output shaft;  
       an electricity storage device;  
       a power transmission device for transmitting an energy between the engine and the electricity storage device as well as a drive shaft of the vehicle, the power transmission device having an input shaft and an output shaft; and  
       an electronic control unit for controlling the power transmission device,  
       wherein the power transmission device includes:  
       a first rotary electric machine having a first rotor mechanically connected with the output shaft of the engine through the input shaft of the power transmission device; and  
       a second rotor connected with the first rotor such that an electromagnetic energy is transmitted between the second rotor and the first rotor and mechanically connected with the output shaft of the power transmission device, the first rotary electric machine transmitting an energy between the engine and the electricity storage device;  
       a second rotary electric machine having a rotor mechanically connected with the output shaft of the power transmission device and transmitting an electromagnetic energy between the electricity storage device and the output shaft of the power transmission device; and  
       a rotation restraining mechanism fixing the output shaft of the engine or the input shaft of the power transmission device unrotatably, and  
       wherein the control unit restrains the output shaft of the engine or the input shaft of the power transmission device unrotatably by driving the rotation restraining mechanism when the vehicle moves in reverse.  
     
     
       21. A control apparatus according to claim  20 , wherein the rotation restraining mechanism restrains the input shaft of the power transmission device. 
     
     
       22. A control apparatus according to claim  20 , wherein the control unit releases the restraint although the vehicle is moving in reverse, when a remaining capacity of the electricity storage device is less than a predetermined lower limit value. 
     
     
       23. A control apparatus according to claim  22 , wherein the control unit restores the restraint after the restraint is released, when the remaining capacity of the electricity storage device reaches an upper limit value greater than the lower limit value by more than a predetermined value while the vehicle is moving in reverse. 
     
     
       24. A control apparatus according to claim  20 , wherein the control unit distributes outputs of the first and second rotary electric machines such that loss of the power transmission device is minimum, when the vehicle moves reverse. 
     
     
       25. A control apparatus according to claim  24 , wherein the control unit determines loss of the power transmission device based on a charge/discharge power of the electricity storage device. 
     
     
       26. A control apparatus according to claim  20 , wherein the control unit distributes the outputs of the first and second rotary electric machines such that loss of the power transmission device is minimum, based on a speed of the vehicle and a vehicle driving torque, when the vehicle is moving in reverse.